html,
body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
}
#header {
  width: 100%;
  height: 64px;
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
}
#tool {
  position: fixed;
  left: 0;
  top: 64px;
  height: calc(100% - 64px);
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
  font-size: 14px;
}
.tool-item {
  padding: 8px 10px;
  cursor: pointer;
  transition: all 0.3s;
  box-sizing: border-box;
}
.tool-item:hover {
  background-color: #29e;
  color: #fff;
}
